JPS6085251A - Contactless igniter for internal-combustion engine - Google Patents

Abstract

PURPOSE:To restrain the energy loss in an engine by placing the output signal of a number of rotations-voltage conversion circuit over the reference level of an auxiliary ignition signal generating circuit and by gradually decreasing, with an increase in the number of rotations, the connection time of a discharge loop in the higher rotation range. CONSTITUTION:The output signal from a number of rotations-voltage conversion circuit, which consists of resistances 17-21, a comparator 43, a transistor 46, and a condenser 39, is placed over the reference voltage of a comparator 44. Thus, as the number of rotations of an engine increases, the operation time of a DC.DC converter, which consists of resistances 24 to 31, a zener diode 32, condensers 40, 41, a comparator 45, transistors 47, 48, diodes 35, 36, and a step-up transformer 49, can be decreased within the time that a rotor 5a is opposed to a side plug 5b, and can be arbitrarily limited during the maximum operation. In this way, a proper ignition signal can be generated according to the rotation of the engine, minimizing the energy loss.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a non-contact ignition device, and particularly relates to an ignition signal that short-circuits the spark plug electrodes of each cylinder, and a discharge loop of the spark plug due to the short circuit between the electrodes. The present invention relates to a non-contact ignition device for an internal combustion engine that includes an auxiliary ignition section that generates an auxiliary ignition signal that sustains the ignition.

[Background of the invention]

Conventionally, DC-
A DC converter is used. For example, the patent application 1983-
D in No. 39002, Japanese Patent Application No. 58-76164, etc.
When generating an auxiliary ignition signal using a C-DC converter, a method has been used in which the duration of a spark plug discharge loop due to a short circuit between electrodes is controlled to a constant time. However, since the time during which the distributor rotor and side plugs face each other decreases as the speed increases, controlling the duration of the discharge loop to a constant value will result in less time when the rotor and side plugs are not facing each other in the high speed range of the engine. An auxiliary ignition signal is generated and the spark runs out. At this time DC
- There was a problem in which the DC converter was under no load and premature ignition occurred at the next ignition.

Therefore, a method has been proposed in which the duration of the discharge loop is decreased as the engine speed increases. For example, an apparatus shown in FIG. 1 has been proposed that adopts this method. However, the device shown in FIG.
There is a drawback that the operation time of the DC-DC converter is longer than necessary in the constant rotation range from the time of startup, which increases energy loss. Furthermore, in the high rotation range of the engine, DC-DC
The operation of the converter became unstable, and it was necessary to stop the DC-DC converter at a certain appropriate rotation speed. The conventional device will be explained below with reference to FIGS. 1 to 3.

In Fig. 1, when the low power of battery 1 is applied to key switch 2,
It is supplied to the valley part of the ignition device 3 via. The ignition device 3 includes a pickup coil 3a for detecting the engine, a control circuit for controlling the detection output of the pickup coil 3a, and a power transistor 3b operated by an output signal of the control circuit. 4 is an ignition coil, and 5 is a rotor 5a.

A power distributor having a side plug 5b, and ignition plugs 6 to 9 are installed in each cylinder.

Resistors 17-24, Zener diode 31, capacitors 33, 34, comparator 36, transistor 37.3
8, diodes 29, 30, step-up transformer 39 j5
The DC-DC converter is configured with a resistor of 10~
16.40, diodes 25-27, comparator 35
, and the capacitor 32 constitute a one-shot multi-circuit that determines the operating time of the DC-DC converter.

Further, the ignition device 3 is configured to detect an AC signal (signal Vp in FIG. 2(a)) synchronized with the engine using a pickup coil 3a, and to control the ON time of the power transistor 3b using a control circuit. .

When the power transistor 3b turns on, the primary current 1 shown in FIG. Due to the energy, a negative secondary voltage v2 shown in FIG. 2(C) is generated on the secondary side of the ignition coil 4.

This voltage is applied to the spark plugs 6 to 9 via the rotor 5a and side plug 5b of the power distributor 5, and the insulation between the electrodes of the spark plugs 6 to 9 is broken. Normally, in order to break the insulation between the electrodes of spark plugs 6 to 9, a voltage of -10kV to -2 is applied to these electrodes.
It is necessary to apply a high voltage of 0 kV.

When the insulation between the electrodes of the spark plug 6 is broken, the route is GND → spark plug → side plug 5b in the power distributor 5 → rotor 5a → secondary coil of the ignition coil 4 → capacitor 34 of the DC-DC converter → GND route. A discharge loop is formed in the second
A secondary current I2 shown by the solid line in Figure (d) flows.

In addition, when the DC-DC converter is not operated, that is, when the ignition device 3 and the ignition coil 4 are used to cause the spark plugs 6 to 9 to spark, the discharge duration (tl shown in (C) and (d) in Figure 2) ) is approximately 1 m5 ec, and the discharge ends at point N in FIG. 2(C). Moreover, the peak value of the discharge current I2 shown in FIG. 2(d) (not including the capacitance discharge) is 40~
It is 50mA.

As shown in FIG. 2(C), when the insulation between the spark plug electrodes is broken, the voltage required to continue discharging the spark plugs 6 to 9 is about -2 kV. Therefore, if a medium-high voltage of about -2kV generated by a DC/DC converter is superimposed on the secondary side of the ignition coil 4 after dielectric breakdown between the electrodes of the spark plugs 6 to 9, the discharge at the spark plugs 6 to 9 can be suppressed. It becomes possible to continue. Therefore, the output voltage of the DC-DC converter must be controlled with appropriate timing and operating time from startup to high speed.

If you overlap it while doing so, the fuel efficiency of the engine will improve.

Leads to improved efficiency.

Next, the DC-DC converter will be explained.

The power supply line of the comparator 36 is stabilized by the resistor 22 and Zener diode 31. diode 29
is for protection of the power transistor 38.

= anti-i'y~21, capacitor 33, comparator 36
The oscillator is configured by, and the output signal of the oscillator is
Since the voltage is applied to the base of the transistor 37 via the resistor 33, switching of the transistor 37 is repeated. When the transistor 37 is 01” F, the resistor 24
A base current flows into the power transistor 38 via
The power transistor 38 is turned on, and current flows through the primary coil of the step-up transformer 39. The step-up transformer 39 is of a forward type, and the power transistor 38 is
When N is applied, medium-high voltage is generated in the step-up transformer 39 and GN
D → capacitor 34 → diode 30 → step-up transformer 3
The capacitor 34 is charged through the route of the secondary coil 9. When the transistor 37 is turned on, the power transistor 38 is turned off, and the flybank pressure generated at this time is blocked by the diode 30. Due to the switching operation of the power transistor 3B, the voltage at the connection point between the capacitor 34 and the diode 30 on the anode side becomes about 12 kV.

As mentioned above, in the ignition device 3, when the insulation between the electrodes of the ignition plugs 6 to 9 is broken, the following happens: GND → ignition plug → side plug 5b of the power distributor 5 → rotor 5a → secondary coil of the ignition coil 4 → A discharge loop is formed along the route from capacitor 34 to GND, and discharge current 2 flows. On the other hand, capacitor 3
4 is charged to about -2 kV while the oscillator is operating, the discharge current of the capacitor 34 is superimposed on the discharge current 2, and the overall α current of the spark plugs 6 to 9 is As shown by the broken line in FIG. 2(d), the voltage continues until point B where the oscillator stops operating, and the secondary voltage 2 shown in FIG. 2(c) also continues until point B.

Resistors 10-16, 40, diodes 25-27, comparator 35, and capacitor 32 constitute a shot multi-circuit. The collector voltage VI of the power transistor 3b of the ignition device 3 has a waveform shown in FIG. 25 to the non-inverting terminal of the comparator 35, and becomes a one-shot multi trigger signal.

That is, when the non-inverting terminal voltage of the comparator 35 is higher than the inverting terminal voltage in synchronization with the OFF operation of the power transistor 3b of the ignition device 3, the output terminal of the comparator 35 becomes high level and the diode 28 becomes non-conductive. . At this time, the oscillator capacitor 33 repeats charging and discharging, so the DC
-]) C converter operates and the capacitor 34 is charged.

When the output terminal of the comparator 35 becomes a low level, the voltage at the inverting terminal of the comparator 36 is equal to the forward drop of the diode 28, approximately 0.7V, and the voltage at the non-inverting terminal is higher, so the output of the comparator 36 is always at a high level. becomes. Therefore, the transistor 37 is turned on and the power transistor 38 is turned off, so that the DC-DC converter stops operating. The output terminal voltage waveform of the comparator 35 is shown in FIG. 2(f), and the collector voltage waveform of the transistor 37 is shown in FIG. 2(g). Figure 3 (ll), (no,
A collector voltage waveform V1 of the power transistor 3b of the ignition device 3 is shown. Figure (h) shows the speed at low speed (Figure 4 shows the speed at high speed).Also, the resistor 16 has a high resistance of about 3MΩ.

Next, the effect at low speeds will be explained.

The collector voltage Vl of the power transistor 3b is
3(i), a trigger waveform signal as shown in FIG. 3(i) is applied to the non-inverting terminal of the comparator 35 due to the flyback voltage.

Since the peak voltage value of this trigger signal is larger than the inverting terminal voltage of the comparator 35 (divided voltage of the resistor 12 and 13), the output voltage of the comparator 36 is at a high level. , through resistor 16, resistor 15.14.11 and capacitor 32
It is charged according to a more determined time constant. Resistor 16 is approximately 3
Since it has a high resistance of MΩ, it hardly participates in charging the capacitor 32. 1 generated in the resistor 11 due to this charging current
While the u pressure V5 is greater than the inversion terminal voltage v4 (Vr, >
V4), the output of the comparator 36 remains at a high level. The waveforms of the voltages Vs and V4 are shown in Figure 3 (k) K.
show.

When the voltage V5 becomes <V4, the output terminal of the comparator 36 becomes a low level, and the current flows through the resistor 15, the discharge current of the capacitor 32 which flows through the resistor 16, and the diode from the inverting terminal of the comparator 36 of the oscillator. 28 to draw the current flowing through it. The electric charge of the capacitor 32 is determined by the time constant determined by the capacitor 32 and the resistor 16, but at constant speed, the ignition interval is longer than the discharge time, so the contact voltage V3 of the cathode of the capacitor 32 and the diode 27 is As shown in Figure 3 U), it decreases to OV.

However, in the high speed range, the ignition interval is short and the contact voltage V
3 never drops to OV as shown in FIG. 3 (11)K, and the capacitor 32 is always charged.

In this state, when the trigger signal shown in FIG. 3) is applied, the capacitor 32 is not completely discharged, so the peak value of the voltage V5 decreases compared to when the speed is low. Therefore, at high speeds, the time during which V5>v4 becomes shorter is shorter than at low speeds. That is, the voltage Vs.

The v40 waveform becomes as shown in FIG. 3 (0).

The time when VII>v4 in FIGS. 3(k) and (o) is a one-shot time, and the output terminal of the comparator 35 is at a high level, and the oscillator generates power '-transistor 3.
8 is driven, the DC-DC converter operates.

DC- of the apparatus shown in FIG. 1 configured as above.
The speed characteristics due to the operation of the DC converter are shown by the two-dot chain line in FIG.

From FIG. 4, it can be seen that in the case of the apparatus shown in FIG. 1, the operating time of the DC-DC converter becomes longer than necessary in the low speed rotation range of the engine from the time of startup, resulting in an increase in energy loss. Furthermore, when the peak value of the non-inverting terminal voltage V5 of the comparator 35 approaches the inverting terminal voltage V4, there is a region in which the operation of the comparator 35 is unstable and repeats repeated discharges and non-discharges. Therefore, in the conventional device, it was necessary to stop the operation of the DC-DC converter at an appropriate rotation speed.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a non-contact point for internal combustion engines that can distribute and supply an efficient and stable ignition signal to each cylinder according to the rotation of the engine. The purpose is to provide an ignition device.

[Summary of the invention]

In order to achieve the above object, the present invention provides an ignition section that sequentially supplies an ignition signal synchronized with engine rotation between the spark plug electrodes of each cylinder to short-circuit between the electrodes of each spark plug, and a short-circuit between the electrodes. The auxiliary ignition section supplies the ignition section with an auxiliary ignition signal that sustains the discharge loop of the ignition plug, and the pulse signal that generates a differential pulse signal in synchronization with engine rotation in the fully equipped non-contact ignition system for internal combustion engines. a generation circuit, a rotation speed/pressure conversion circuit that generates a signal at a level corresponding to the rotation of the engine;
The auxiliary ignition section is composed of an auxiliary ignition signal generation circuit that compares the reference level with the level of the differential pulse signal and generates an auxiliary ignition signal when the level of the differential pulse signal exceeds the reference level, and converts the rotation speed and pressure. The output signal of the circuit is superimposed on the reference level of the auxiliary ignition signal generation circuit, the duration of the discharge loop in the engine's low rotation range is maintained at a constant time, and the duration of the discharge loop in the engine's high rotation range is maintained at a constant time. The feature is that the number is gradually decreased as the number increases.

[Embodiments of the invention]

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 5 shows the configuration of a preferred embodiment of the present invention.

In FIG. 5, the ignition device 3, ignition coil 4, and power distributor 5 included in the ignition section are the same as those in the conventional device shown in FIG. The same symbols are added to the same numbers, and the explanation thereof will be omitted. In addition, the comparator 4 is connected to the resistor 29 and the Zener diode 32.
Power lines 2 to 45 are stabilized. Also, resistance 2
4 to 28, a capacitor 40, and a comparator 45 constitute an oscillator! D. The configuration of the DC-DC converter is similar to that shown in FIG. However, the symbols are different from those in FIG.

A pulse signal generation circuit that generates a differential pulse signal in synchronization with the rotation of the engine includes resistors 10 to 15, a diode 34, a Zener diode 33, a capacitor 37, and a comparator 4.
2, a capacitor 38, and a resistor 1
6. It is composed of a differential circuit including all diodes 50.

Further, a rotation speed-voltage conversion circuit that generates a signal at a level corresponding to the engine rotation speed includes resistors 17 to 21 and a comparator 43.
, a transistor 46, and a capacitor 39.

An operating time determining circuit for the DC-DC converter, which together with the DC-DC converter constitutes an auxiliary ignition signal generation circuit, includes resistors 22 and 23 and a comparator 44.

Collector voltage v of power transistor 3b of ignition device 3
1 is divided by resistor 10.11 and diode 34
is applied to the non-inverting terminal of the comparator 42 via the . A capacitor 37, a resistor 12, and a Zener diode 33 are connected between the non-inverting terminal of the comparator 42 and GND to smooth the non-inverting terminal voltage V7.

The inverting terminal of the comparator 42 is the Zener diode 32
A voltage obtained by dividing the Zener voltage Vz by resistors 13 and 14 is applied as a reference voltage.

Shown in (p) + ('). Figures φ to (1) are at low speeds, and figures (u) to (y) are at high speeds.

As shown in the figures (p) and (u), the output terminal of the comparator 42 becomes high level in the interval where v7>v6. The output voltage of the comparator 42 is applied to the non-inverting terminals of the comparators 43 and 44 via a differentiating circuit including a capacitor 38 and a resistor 16. Differential range pressure■8 is comparator 4
It is compared with the inverted terminal voltage v9 of 3, and Vs>V! The output voltage VLG of the comparator 43 becomes high level in the 10th period. In addition, comparator 4 is shown in (Q) and (V) in Fig. 6.
3 shows the non-inverting terminal voltage waveform and the inverting terminal voltage waveform,
(r) and (b) show the output voltage waveform of the comparator 43.

The peak value of the differential voltage v8 is the value obtained by dividing the Zener voltage Vz of the Zener diode 32 by the resistor 15.16,
The charging time constant is also determined by the resistors 15 and 16 and the capacitor 38, and the inverting terminal voltage v9 of the comparator 43 is also the voltage divided by the Zener voltage Vzk resistor 17.18, so the output terminal of the comparator 43 becomes high level. The section is a fixed amount of time. Also, when VIO becomes high level,
A pace current flows through the transistor 46 through the resistors 19 and 20, turning on the transistor 46 and charging the capacitor 39 through the resistor 21.

The charge in the capacitor 39 is constantly discharged via the resistor 23, but the transistor 46 is turned on for a certain period of time every cycle to charge the capacitor, so the voltage charged in the capacitor 39 increases as the engine speed increases.

In addition, when the key switch is ON, the engine is 0 [at one time, the charging voltage of the capacitor 39 is the zener voltage Vz of the resistor 22.2
The minimum value of the charging voltage of the capacitor 39 is limited by this divided voltage. Resistance 22.
By comparing the divided voltage Vll and the differential waveform Vs according to 23,
9. The maximum operating time of the DC-DC converter is determined.

The non-inverting terminal voltage Vs and the inverting terminal voltage Vs+'ft of the comparator 44 at low speed are shown in FIG. 6(s) K. v8
〉In the v-th interval, the output terminal of the comparator 44 is at a high level, and during this high level interval, the C-DC
This is the operating time of the converter.

FIG. 6(1) shows the output terminal waveform of the comparator 44. At high speeds, the relationship between ■8 and Vll becomes the waveform shown in FIG. 6(X), and the output terminal waveform of the comparator 44 also has a shorter noise level section than at low speeds, as shown in FIG. 6(y).

DC- of the device in this embodiment configured as above.
The speed characteristic of the operating time of the DC converter is the characteristic shown by the dashed line in FIG. That is, the device according to the present embodiment superimposes the output signal of the rotation speed-voltage conversion circuit on the reference voltage of the comparator 44, thereby reducing the operating time of the DC-DC converter as the rotation speed of the 11th motor increases. It becomes possible to reduce the time during which the side plug 5a and the side plug 5b face each other, and it also becomes possible to arbitrarily limit the leftmost operating time of the DC-DC connector.

Therefore, energy loss from startup to low speed can be reduced. Further, in this embodiment, since a method is adopted in which the output signal of the rotation speed/pressure conversion circuit is superimposed on the reference voltage of the comparator 44, DC, -
1) The operation of the C converter will not become unstable. Furthermore, in the embodiment, when the inverting terminal voltage Vll of the comparator 44 exceeds the peak (normal) of the non-inverting terminal voltage V+s, the operation of the DC/DC converter stops.
Since there is no need to stop the DC-DC converter at a rotation speed of 1, a stop circuit is not required, and miniaturization is possible.

〔Effect of the invention〕

As explained above, according to the present invention, an appropriate ignition signal can be generated according to the rotation of the engine, so that there is a significant effect that energy loss can be suppressed to a minimum.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a conventional device, Figs. 2 and 3 are waveform diagrams of various parts of the device shown in Fig. 1, and Fig. 4 is a DC-DC converter of the conventional device and the device according to the present invention. FIG. 5 is a configuration diagram showing an embodiment of the present invention, and FIG. 6 is a waveform diagram of each part of the device shown in FIG. 5. 3...Ignition device, 3a...Pickup coil, 3
b...Power transistor, 4...Ignition coil, 5
...Distributor, 5a...Rotor, 5b...Side plug, 6-9...Ignition plug, 35-36.42-45.
...Comparator, 39.49...Step-up transformer. Agent Patent attorney Akio Takatsuka 7・-・ ・ 1 N1, 1 Live 2 fertilizer ('j)

Claims (1)

[Claims] 1. An ignition unit that sequentially supplies nine ignition signals between the spark plug electrodes of each cylinder in synchronization with engine rotation to short-circuit between the electrodes of each spark plug, and maintains the spark plug discharge loop due to the short circuit between the electrodes. An auxiliary ignition section that supplies an auxiliary ignition signal to the ignition section, a pulse signal generation circuit that generates a differential pulse signal in synchronization with the rotation of the engine, and a pulse signal generation circuit that generates a differential pulse signal in synchronization with the rotation of the engine. an auxiliary ignition signal that compares the reference level with the level of the differential pulse signal and generates an auxiliary ignition signal when the level of the differential pulse signal exceeds the reference level; The output signal of the positive conversion circuit is superimposed on the reference level of the auxiliary ignition signal generation circuit, and the duration of loose discharge in at least the high rotation range of the engine is determined. A non-contact ignition device for an internal combustion engine, characterized in that the ignition is gradually reduced as the engine speed increases.